Google's interview process is legendary for several reasons, but they're not alone in taking hours to get to know their applicants. Despite a trend towards longer interviews, most people make up their minds after a few seconds. Here's why.

Carlin Flora, writing for Psychology Today, points out that our brains have a tendency to take a little snapshot each time we meet someone and that snapshot colors how we view them going forward. Flora explains:

The answer lies in part in how the brain takes first-impression Polaroids-creating a composite of all the signals given off by a new experience. Psychologists agree that snap judgments are a holistic phenomenon in which clues (mellifluous voice, Rolex watch, soggy handshake, hunched shoulders) hit us all at once and form an impression larger than their sum.

What ends up being most relevant, however, is the presence of a genuine smile (something we showed you how to do earlier today). People can pick up on a smile from up to 30 feet away, and tends to make them feel welcome and good. This isn't far from obvious, but when you consider how snap judgments play a huge role in first impressions you can really start to see how important a smile can be.

For more (very interesting) information on first impressions, thin-slicing, and snap judgments, be sure to check out the full article.